An operator service center provides operator services to callers or subscribers. An operator workstation is used by an operator in an operator service center for assisting subscribers connected to a public telephone network to make a call or to answer their questions.
An operator workstation must meet several criteria which are standard in the industry (as specified in Bellcore's OSSGR Sections 7 and 21 Performance Requirements, Issue 1, February 1991) pertaining to transmit and receive signals to protect the operator who uses the operator position all day. These criteria specify sidetone level, volume level, limiting and echo control.
Sidetone is a portion of operator speech which is fed back to the receive path to permit the operator to hear his or her own voice. The feedback operator speech is attenuated to prevent the operator from lowering his or her own voice and preventing insufficient signal levels from being transmitted. Echo from an operator's voice signal in a telephone system can occur at the junction of a four-wire to a two-wire interface. Echo control involves calculating the maximum allowable level of echo from the level of the operator's transmit speech and inserting loss in the receive path at the estimated time of arrival of the echo. Limiting looks for high tones in the receive path and inserts loss to attenuate the high tones to protect the operator's hearing. Volume control allows for lowering or increasing the volume level of incoming voice signals.
The audio signals from the public telephone network must be routed to the operator workstations to control these specific characteristics. This would allow the operator to control the audio signal that he or she hears through a headset coupled to the workstation.
Prior approaches have implemented these various controls utilizing analog circuits which are relatively harder and more expensive to manufacture and more prone to errors. Analog circuits also require adjustment of all parameters during manufacture. Thus, the quality of delivered devices might suffer, resulting in some loss in customer goodwill.
Other prior approaches implemented these controls utilizing digital circuits to process speech digitally to provide the operator using the operator position with complete control over echo control, acoustic limiting, sidetone control and volume control. While this approach may be more reliable than the analog approach described above, it cannot guarantee that the operator adjustments of the audio criteria will meet or exceed the Bellcore OSSGR requirements for an operator position.
In addition to providing an operator with the ability to control the audio characteristics of audio signals, it is also desirable for an operator workstation to provide the operator with some automated mechanism to generate voice messages that can be played back to the subscribers. This is desirable because more and more operator service centers are relying on automated voice processing to generate greeting and response messages to service caller inquiries. The automated voice feature alleviates the need for an operator to vocalize greetings and responses to subscribers.
It is also desirable to provide both an operator and an operator supervisor with access to incoming calls so communications with subscribers can be monitored. This allows a supervisor to roam the operator service center with a headset on and simply plug into an operator workstation to monitor the servicing of a subscribers call. Prior operator workstations that have provided this functionality have been unable to prevent a signal loss from occurring on the connection between the operator and subscriber when the supervisor connects to the workstation. This signal loss can result in the operator or subscriber having to repeat themselves which thereby reduces the efficiency of the service.
Prior art approaches have not presented a solution to the above problems in a single board that could be added to operator workstations. Since the platform for most operator workstations are personal computers, the amount of space available in the personal computer to provide additional functionality becomes critical.